Porsche Boxster S PDK
The Porsche Boxster starts off with the major advantage that it is perhaps the best-balanced, sweetest-handling and most agreeable sports car at a price that is affordable to many – if not to first-time buyers or to motorists already struggling to keep up their mortgage payments.
Yet with that status as one of the very best of its kind also comes a certain risk: any tinkering with the Boxster's specification or fine-tuning of its successful recipe brings with it the danger that perceived perfection could be disturbed and that those who like how it feels will perceive this as a degradation rather than enhancement.
That was the risk Porsche ran when adapting its seven-speed PDK dual-clutch transmission for the Boxster roadster and its closed-coupé sibling, the Cayman. Previous Tiptronic S versions of these models using torque converter automatics had sold in reasonable numbers to city dwellers and those insistent on two-pedal driving, but had been spurned by hardline enthusiasts as not responsive or satisfying enough to be a real Porsche. Yet with the PDK already well received in the pricier 911 Carrera, it was likely that the DCT system could satisfy a dual requirement in the smaller car – to provide the option of automatic operation without alienating enthusiasts, and to deliver not only improved performance but better CO2 figures too.
The introduction of the PDK to the Boxster/Cayman series coincides with a round of changes which, among other developments, sees the adoption of direct injection for the mid-mounted flat six engines; in the case of the 3.4 liter Boxster S test car, power rises to 310hp, with CO2 emissions falling to 221g/km -- corresponding to gasoline consumption of 24.2 US mpg.
The first thing that is noticeable about the new drivetrain is the engine’s deeper, more powerful exhaust note – a fuller sound that hints at its extra power. The central gear selector moves rearwards through the standard Park, Reverse and Neutral positions before reaching Drive, for fully automatic operation; a slot to one side selects sequential manual operation, with a push forward for an upshift and a pull towards the driver for a downchange. This is becoming the industry standard arrangement; previous Tiptronic S Porsches had been different.
Where Porsche still is different is in its steering wheel transmission controls, something that has come in for criticism on the 911. Instead of paddles mounted behind the wheel, Porsches have a large button on the outer edge of each spoke: pushing this button forwards with the thumb triggers an upshift, while pulling it rearwards with the fingertips from behind the wheel gives a downshift. Both buttons have exactly the same action, in contrast to paddle arrangements where the left is the downshift and the right the upshift. There are arguments both ways, of course, but after driving the Boxster it is clear that the Porsche arrangement works just as well as any other.
Leaving the transmission to its own devices in D gives very smooth and relaxed travel, the driver able to enjoy imperceptible, seamless upshifts and the added crispness of the new engine. Harder driving produces just the response one would want; more revs, quicker reactions and a greater feeling of involvement – and the steering wheel shift controls can be used for the rare occasions that the transmission's automatic operation needs to be overridden.
Selecting Sport mode on the dash-mounted switch bank produces a sharpening of the car's responses: the damping becomes firmer, the shifts quicker—but still smooth - and the revs higher; even though in auto operation the revs through the gears are held longer, the car quickly settles down as the driver reduces the throttle openings. Again, the system has that ability to sense what is wanted, prompting downshifts when braking before bends and, in manual mode, triggering beautifully-synchronized throttle blips when shifting down the box. For low-speed urban driving, however, it is less well suited: creeping forward in traffic is a jerky, sensitive process.
Available in all modes is a novel feature labeled ‘tap down’. By giving a short tap on the throttle pedal - rather like clicking the button on a computer mouse - the transmission snaps down a ratio on demand. When it works it is very satisfying, but it takes some practice to achieve just t he right type of tap to trigger it reliably.
Sport Plus, also selectable, is more extreme still - in fact, it is so aggressive as to be akin to a track or race setting. It is very jerky at low speeds, holding first gear – even on a light throttle – right the way round to the red line. Accelerating hard, it shifts up precisely at the red line each time, the lightning shifts slotting in with a firm push, if not the hard slam of some track-biased cars. Even at a steady 100 mph (160 km/h) on a test track it stays in sixth gear, shifting up to seventh only after an extended steady-throttle period.
In Sport Plus, Porsche has provided just the sort of extreme mode that will please the serious-minded, hard-driving owner out to extract maximum performance. There is also the option of the S port Chrono package, which adds full launch control for authentic race starts – ands shaves 0.2 seconds off the 0-100km/h (62mph) acceleration time in the process to bring it to a snappy 5.0 seconds.
For the more everyday driver, however, the more extreme elements of the Sport Chrono package may be of limited appeal and the Sport Plus mode is likely to be too stressful: what really makes the Boxster/Cayman PDK such a successful solution is the way in which the transmission's already delightful responses can be sharpened just the right amount whenever the driver so desires, adding a final layer of telepathic sophistication to a car that has always been one of the very best. As to whether the PDK version of the Boxster is preferable to the standard six-speed manual, that's an altogether trickier question. In any other vehicle a DCT as excellent as Porsche’s would be an absolute must-have; on something that's already as close to ideal as the manual Boxster, it's not quite so straightforward to justify. What one loses in tactility and direct mechanical connectedness on the open road is regained in town, when PDK is clearly smoother and easier.
Best, perhaps, to declare it an honorable draw.
Story Filed: 7/14/2009
By Tony Lewin, managing editor DCTfacts.com